Many systems utilize displays to present information in the form of images, video and/or text to users. Displays effectively transmit information, but are constrained by being two dimensional in nature. Human ocular capabilities, however, afford the perception of images in three dimensions. Three dimensional (“3D”) technologies are designed to address these ocular capabilities. Providing more realistic 3D performance is especially important in activities such as viewing videos, interactive games, as well as computer animation and design. Creating a 3D display can involve delivering different view-point images to each of the user's eyes. The solutions for delivering different viewpoints can be classified as either stereoscopic 3D displays, holographic 3D displays, or autostereoscopic 3D displays.
Stereoscopy displays present slightly different images to each eye, resulting in the perception of a 3D image. Stereoscopic 3D display solutions typically involve the user wearing active equipment (e.g. headwear). The headwear may comprise: separate displays in front of each eye or shutters, which synchronize the delivery of each eyes' viewpoint with the display. Alternatively, passive eyewear, such as polarized glasses or colored filters, can be worn. Each of these solutions may necessitate the user to purchase, wear and have available specially designed headwear. Further, each solution may require specially encoding the information to interact with the specially designed headwear.
Holographic 3D displays reproduce a light field identical to that which emanated from the original scene. These displays optically store, retrieve and process information. Holographic 3D displays may not require specially designed headwear, but they may require specialized hardware such as spinning mirrors covered with special holographic diffusers and high speed projectors and require a complex Digital Visual Interface (DVI). These components may require very high data-rates and may add exorbitant expense.
Autostereoscopic 3D displays typically use solutions similar to stereoscopic 3D displays, but may not require specially designed glasses or other headwear. For example, parallax barrier displays use two separated layers. On the first layer, a combination of the left and right eye views are arranged. While a second layer, consisting of opaque and transparent barriers, for example, may restrict the light of each viewpoint arriving at the opposite eye. The positioning of the first and second layer creates “viewing diamonds” which limit the user to specific positions where images can be perceived in three dimensions. When a user positions his head in these “viewing diamonds,” each eye is delivered a different image, creating the perception of a 3D image.
These known schemes for creating an autostereoscopic 3D display have a number of shortcomings. Firstly, because of the fixed configurations of parallax barrier displays, viewing may be constrained to pre-defined “viewing diamonds.” Offset viewing using head detection to either adjust the barrier sideways or change the separation of the display/mask may be used to dynamically adjust the “viewing diamonds,” however, if the user's head is tilted or twisted relative to the display, or the user's eyes are effectively at different distances from the display causing distortion in the upper and lower bounds of the image. To compensate for these off-angle corrections, a parallax barrier system may necessitate a complex barrier/display configuration. Secondly, because of the finite viewing distance, the apparent distance between pixels in the display and the barrier caused by their separation may result in the display and barrier moving in and out of phase relative to each other across the display plane. This phase shift appears as very large dark bands, (i.e. “banding”), running vertically down the image and becoming more pronounced as the viewing angle of the display increases.
Therefore, a need exists for an autostereoscopic display that maximizes a user's available positions.